How to release Unity Memory from iOS App

I am building an iOS app application which has Unity Game as a submodule, to Integrate that I have created an Instance of UnityAppController and placed UnityGLView in mine ViewController view.

On Exit I have added UnityExitHandler removed the UnityGLView from mine view hierarchy for the very first time its working fine and memory of Unity is also released which I have seen on profiler, but when I re-initialize UnityAppController usning init application got crashed.

I want to know that is this is the right way for integrating Unity Game as a module in iOS App, second what is the correct way to release the memory of Unity when user exit the game.